The present invention relates to a method for positioning animal related means, e.g. teat cups, relative to a defined part of an animal, e.g. a milking animal, as is set forth in the preamble of claim 1, more specifically to a method to initialize an automatic positioning device to utilize a sequence of movements associated with said animal. The present invention also relates to a control device.
Present automatic milking systems comprise an automatic positioning device, such as a robot arm with identifying means. The positioning device normally utilizes a predetermined sequence of movements to locate and identify teats on an udder of a milking animal. The udder of a milking animal, such as a cow, may have different shapes and the teats on the udder may be positioned differently. In spite of these variations a single sequence of movements is normally used, which results in that the teats on some animals cannot be found within a predetermined time limit. Such animals may then have to be rejected since they cannot be milked using this system.
Furthermore, a shift in position of the teats occurs over time, in particular in the case of a young animal, in which the size of the udder increases with growth, which in turn gives rise to greater distances between teats. If substantial changes arise, the animal may be rejected by the system.
In case of an adult animal it has been found that fluctuating milk yield occurs per visit to the milking robot. Due to the fact that the milk yield varies will the teat position per milking animal vary through greater or lesser tension of the udder, affected by the fluctuating quantity of the milk present therein.
Furthermore, during the period between two calvings the yield increases during the first months and decreases again thereafter. This will also lead to a change in the distances between the teats.
In WO 96/20587 a method is disclosed for regularly checking the position of the teats for positioning teat cups on milking animals addressing the problem related to teats that are not in the same position on a subsequent visit. Readjustments of he the position is necessary, which is recorded as a new position for the next visit. The positioning of the teat cups on to the teats is initially done manually to get an initial position of the teats. During the checking only the adjustments from the initial position is stored.
This way of introducing a new animal to an automatic milking system is time consuming, especially if the milking system is introduced to a stock of animals.
The object with the present invention is to provide a method and a control device for positioning teat cups on a milking animal which overcomes the prior art problems.
The object is achieved by a method for positioning at least one animal related means relative to at least one defined part of an animal, said animal occupying a defined space provided with an automatic positioning device, said method comprising the steps of:
obtaining an identity of said animal,
determining a class to which the animal belongs among a plurality of classes corresponding to the identity of said animal, the animal being beforehand assigned to a class based on its individual position of each defined part,
initializing said automatic positioning device to utilize a sequence of positioning movements associated with the class, and
positioning said animal related means using said sequence of movements,
whereby the process for positioning the animal related means is adapted for varying positions of each defined parts of said animal.
The specific problem with introducing a new animal to the above mentioned system is solved by a method according to claim 9.
The object is also achieved by a control device for positioning animal related means relative to defined parts of an animal, according to claim 14.
An advantage with the present invention is that animals with unusually shaped udders, having teats positioned in an undesired way, may still be allowed in the automatic milking system instead of being discarded from the system. A discarded animal must either be sold or slaughtered, which may be costly for the owner of the animals.
Another advantage is that by using a plurality of classes the sequences of movements, adapted for different shapes of udders on the animal, may speed up the process for positioning the teat cups and thereby increase the through-put of animals in the system.
An advantage, with a further embodiment of the invention, is that by assigning a basic sequence of movements for new animals, they may be introduced without any manual assistance.
A still further advantage, with a still further embodiment, is that the behavior of a milking animal is taken into consideration when assigning a sequence of movements, so that, for example, the animals are not disturbed by the positioning device and/or the positioning device is not damaged due to animal movements.